Seeing Red in The Summer Triangle

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Apollo XX
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Seeing Red in The Summer Triangle

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Howdy Folks,

Well, summer is certainly moving along and that asterism known as the summer triangle http://en.wikipedia.org/wiki/Summer_Triangle is now high in the sky at dark. Dark sky treasures abound in the triangle, given that a little thing called the Milky Way traverses it and all. But how about a little trip down the unbeaten path for a change? What say we hunt down something a bit different before the area shifts due west and we’re staring down ol’ man winter once again?

What I’m talking about is seeing red…in the form of carbon stars of course! http://en.wikipedia.org/wiki/Carbon_star If you’ve never seen a carbon star, then you’re in for a real treat. If you have seen carbon stars, then you know they’re well worth going after. Carbon stars display a vivid red/orange/yellow color depending on where they are in their cycle of variability, and they usually stand out in stark contrast to their surroundings. Once you see one, you’ll be amazed at how such a tiny pinpoint of light can dominate the view in the eyepiece. There are carbon stars located all over the sky, so they’re available year round, but the summer triangle just happens to harbor three of them within its boundaries and that’s what we’ll concentrate on today.

Let’s start with the constellation Lyra. Of course Lyra is well known for its night sky wonders like the bright star Vega, the marvelous Double Double, and the dying star display put on by the Ring Nebula. Interestingly, sitting smack-dab in the middle of all this is one of the prettiest carbon stars in the sky. Known as T-Lyra, this star very much holds its own amongst its more famous neighbors. To see it for yourself, use this chart:

Image

For printing convenience and use at the telescope I’m providing inverted images of all the charts in this article. Just save the picture to your computer and print it out.

T-Lyra Inverted:
Image

For our second carbon star challenge we'll move east to the constellation Cygnus. Again, Cygnus is famous form many things, not the least of which is the handsome double star Albireo. It’s an easy hop from Albireo to TT Cyg, the carbon star in Cygnus:

Image

TT-Cyg Inverted:
Image

For our final carbon star challenge, we’ll shift our gaze to the south where we’ll find the constellation Aquila. Located on the southwestern border of Aquila, V-Aql is probably most easily accessed by first finding Lambda Aql, the 3.4 magnitude star on the southwestern tip of the asterism. V-Aql is located about a degree southwest of Lambda Aql:

Image

V-Aql Inverted:
Image

So there you have it, three ways to see some red this summer without even getting mad. If you do happen to take on this challenge, why not share your experiences here so others can enjoy as well? It helps to make our community rich and vibrant, and people really do want to hear about it.

Happy hunting!

Mike M.
"The purpose of life is the investigation of the Sun, the Moon, and the heavens." - Anaxagoras
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AndyG
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Re: Seeing Red in The Summer Triangle

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Thanks for the charts, Mike. I will definitely check these out next clear night.
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Apollo XX
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Re: Seeing Red in The Summer Triangle

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UPDATE: Dark is descending upon us once again, and I hope you're able to take advantage of it. The moon will be rising later and later as the month wears on, until it finally joins hands with the rising sun on the 25th. This means good skies for observing, and tonight was definitely a fine one. The big, puffy clouds of the afternoon gave way to perfectly clear skies by nightfall, even if the seeing was not so good early on. By true darkness things had settled down, and I was able to view all three carbon stars in the "Seeing Red" challenge.

V Aquila was by far the easiest, but also the least vivid as far as the redness goes. I'd call it more of a yellow-red. Very easily located with just the finder scope pointed at Lambda Aquila.

TT Cyg was beautifully vivid red, and was a pleasant star-hop challenge from Albireo. There's no mistaking it once you find it, and it tolerated magnification well. In fact all three of the stars in the challenge were good up to 100x. One of these days I'm going to get some aperture to wield on the sky, and I'll bet these babies are stunning with more light grasp.

I had just visited T Lyra back at the beginning of the month, and I dropped back in on it tonight. Practically at zenith, the sky was about as good as it gets here and this star just pops right out at you in the eyepiece. If I had to guess, I'd say that it was just a bit on the dimmer side than the last time I spied it, and that's entirely possible as these are all of the pulsating variable variety.

Anyone else have a go at it yet?

Mike
"The purpose of life is the investigation of the Sun, the Moon, and the heavens." - Anaxagoras
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AndyG
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Re: Seeing Red in The Summer Triangle

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Mike,

I finally had a chance to look for the carbon stars last night. I had a failed attempt a week or so ago when I setup my scope in the yard, and just as I was about to observe, clouds quickly rolled in. Last night I setup the 8" dob and found V AQL first. It was a bit underwhelming, probably because there happened to be a beautiful double nearby that was drawing my attention.

Next I went for TT CYG. Unfortunately this was right at zenith and I was breaking my neck trying to view through the finder and moving the dob at zenith was just not working. I spied my imaging scope on the other side of the yard and decided I would cheat and just image the thing. So I got that setup and imaging, and moved on to T LYR.

I've got to say that T LYR was just breathtaking. The red color was amazingly rich and deep red and just popped out from the surrounding stars--not because of the brightness, but because of the color. I tried viewing at various magnifications, but I found the color most vivid at low power, ~50X.

Here's the result of imaging TT CYG. About 1 hr exposure, 9 x 2m subs x (R,G,B) binned 1x1, SV 115 refractor w/ 0.8x reducer fl=640 f/5.6, FOV 72 x 96 arc-min. Very little processing, just combined the calibrated subs and stretched. The image cannot do justice to the color you see in an eyepiece. But the camera sure does pick up those dim stars in the background!

(click image for full resolution version)

Image
Last edited by AndyG on Thu Aug 21, 2014 12:48 pm, edited 1 time in total.
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Pete
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Re: Seeing Red in The Summer Triangle

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Andy, your Milky Way image explains why I don't work asteroids in the Milky Way. When there are thousands of stars in the FOV you have a lot of trouble finding a 19th magnitude object that's probably well hidden while occulting one of those stars. And my short exposures are a wee bit noisier than the work you produce.

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Apollo XX
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Re: Seeing Red in The Summer Triangle

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AWESOME job on TT Cyg Andy! Your image conveys the sense of the eyepiece experience very well indeed. Granted there are a lot more stars in your image than there are in the eyepiece, but the RED SPOT smack-dab in the sea of blues, whites, and yellows is an accurate portrayal of the experience. Also, I do agree that there is something about that red pinpoint in the visual view that really makes the effort worth it. And yes, V Acq is less than stunning, but then if it were as good as the others it would be almost too easy. :lol:

Anyone else planning to have a go at it? Like Andy says, the height of TT Cyg or T Lyra (depending on what time you go hunting for them) can be a literal pain in the neck if you're trying to use the finder scope. I like to use a low power eyepiece with the widest field I can get, then I just flip the chart upside down and it matches what I see through the Newtonian. I haven't tried this, but if you're using a refractor I think you could just flip the page over and look through the back of the paper while illuminating the chart from the printed side, then the stars would match what you see in the eyepiece. Of course if you've got goto, just enter the DEC and RA provided on the charts.

Looking forward to hearing from others. Remember, this is one case where seeing red is doctor recommended! 8)

Mike
"The purpose of life is the investigation of the Sun, the Moon, and the heavens." - Anaxagoras
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Paul D
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Re: Seeing Red in The Summer Triangle

Unread post by Paul D »

I plan on getting out early this weekend and checking out those stars Mike.

For those that might be interested in looking at more Carbon Stars here is a list from the Astroleague. http://astroleague.org/files/obsclubs/C ... r-List.pdf

My personal favorite is the Garnet star Mu Cephei in the constellation Cepheus. Here is a finder chart for it. http://freestarcharts.com/images/Articl ... _Chart.pdf
Paul...

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Apollo XX
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Re: Seeing Red in The Summer Triangle

Unread post by Apollo XX »

Paul D wrote:
My personal favorite is the Garnet star Mu Cephei in the constellation Cepheus.
Paul, Mu Ceph is a wonderful red star, and in fact it's in my September Whatzup Challenge! This is great - people will have a little head start! 8)

Mike
"The purpose of life is the investigation of the Sun, the Moon, and the heavens." - Anaxagoras
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Re: Seeing Red in The Summer Triangle

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Which open cluster has a nice red star right in it's midst, is it M44?
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Re: Seeing Red in The Summer Triangle

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ASSNE Prime wrote:Which open cluster has a nice red star right in it's midst, is it M44?
There are a few messier clusters that have carbon stars in them. M 103
http://www.astroimages.de/pics/gallery/ ... 2-crop.jpg

M 67
http://scienceblogs.com/startswithabang ... 200px.jpeg

M44
http://gaskin-astro.org/gallery/main.ph ... alNumber=3

Those are the best of them. Other Messier's have them to but not as obvious as the three above.
Paul...

16" f/5 Night Sky Truss (Midnight Mistress)
10" f/5 Home built Dob with Parks mirror.
Pre-Meade PST
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Meade Travelview Binos 10x50

See that 16" in the sleek black dress? She is all mine. :)
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